Ham & Cheese Brunch casserole

16 slices of white bread, crusts removed and cubed (I don't recommend using a Wonder®-type bread because it doesn't hold up well when baked.)
1 pound of ham, cut into bite-size pieces. You can use deli ham and just slice it up.
2 c shredded cheddar cheese
2 c shredded swiss chees
5 eggs, beaten
3 c milk
1 t ground mustard
1/2 t onion salt OR a small onion diced
2-1/2 c crushed cornflakes
1/3 c butter.
ground pepper to tasteDirections
In a greased 13x9x2-inch baking dish, layer half of the bread, ham, cheddar cheese and swiss cheese.
Repeat.
In a bowl, combine eggs, milk, ground mustard, onion salt or diced onion, and ground pepper.
Give it a good whisk and pour over the layered mixture.
Cover and refrigerate overnight.
Remove from the refrigerator 30 minutes before baking.
Combine crushed corn flakes and melted butter.
Sprinkle on top.
Bake at 375° for 40 minutes or until hot and bubbly.